The background of the present invention is the field of orienting/positioning devices having sensor means supplying orientation information, the input space of which can be changed by a real-world action controlled by actuating means of the orienting/positioning device. In an exemplary application of these devices, the sensor means is oriented/positioned such that a pattern recognized in the input space of the sensor means is transferred to a target position, such as, for example, the center (origin) of the input space coordinates of the sensor means. A typical example of application for the inventive system and method is the focusing operation of a camera of a robot, surveillance by an automatic camera or a pointing device, for example. A robot provided with a camera and an orienting system according to the present invention can thus focus on recognized objects and eventually move towards them in order to manipulate them.
It is a disadvantage of such orienting/positioning devices that they frequently require calibration to work properly. Such a calibration must be done after every change in system geometry (e.g. when the physical relation between a sensor and an actuator of the device is changed), after every modification (e.g. lens replacement, a motor modification) and if the device is used on a changing or uncontrolled environment.
In certain environments a manual calibration by a user is not possible or desired. Furthermore, in case of frequent changes in system geometry, of frequent modification of the sensors or motors or an uncontrolled environment, frequent calibration is very time consuming and laborious.
Therefore, self-calibrating orienting/positioning devices have been proposed. In particular, a self-calibrating sensor orienting system has been described in European patent application No. 04009123.3. There, a method for controlling an orienting/positioning system is proposed, comprising at least one sensor means and actuator means for controlling an orienting and/or positioning action of the sensor means, the method comprising the following steps:                (S1) Evaluating pre-action output information of said sensor means in order to detect the position of a pattern in the input space of the sensor means;        (S2) Deciding on a targeted post-action position of said pattern in the input space of said sensor means;        (S3) Defining a command for the actuator means by mapping any deviation of the pre-action position and the targeted post-action position in the input space coordinates of the sensor-means to actuator control coordinates using a predefined mapping function;        (S4) Orienting/Positioning the sensor means by the actuator means according to the defined command in order to carry out an orienting/positioning action; and        (S5) Detecting the real post-action position of the patterns in the input space of said sensor means;        (S6) Adapting the mapping function used in step (S3) based on any difference of the real post-action position and the targeted post-action position of the pattern in the input space of the sensor means in the order to carry out an incremental adaptive learning of the mapping function, wherein steps S1 to S6 are cyclically repeated at least once using the respectively adapted mapping function.        
However, this approach can fail, if there is external movement, for example a moving person, since any motion of a visible object in the viewing range might distort the adaptation process in that this additional movement might lead to a decalibration of the system or longer calibration process times.
This is a common problem in all scenarios with human intervention.
Therefore, it is an object of the present invention to provide a method of controlling an orienting system and a self-calibrating orienting system, which allows an auto-calibration of the system with accuracy in an environment as described above.